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Link Protection
Link protection is designed to safeguard networks from failure. Failures in high-speed networks have always been a concern of utmost importance. A single fiber cut can lead to heavy losses of traffic and protection-switching techniques have been used as the key source to ensure survivability in networks. Survivability can be addressed in many layers in a network and protection can be performed at the physical layer (SONET/SDH, Optical Transport Network), Layer 2 ( Ethernet, MPLS) and Layer 3 ( IP). Protection architectures like Path protection and Link protection safeguard the above-mentioned networks from different kinds of failures. In path protection, a backup path is used from the source to its destination to bypass the failure. In Link protection, the end nodes of the failed link initiate the protection. These nodes detect the fault responsible to initiate the protection mechanisms in order to detour the affected traffic from the failed link onto predetermined reserved path ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Fiber
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer. Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, some of them being fiber optic sensors and fiber lasers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Two-fiber BLSR
A, or a, is the first letter and the first vowel of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version can be written in two forms: the double-storey a and single-storey ɑ. The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English grammar, " a", and its variant " an", are indefinite articles. History The earliest certain ancestor of "A" is aleph (also written 'aleph), the first letter of the Phoenician alphabet, which consisted entirely of consonants (for that reason, it is also called an abjad to distinguish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiwavelength Optical Networking
Multiwavelength optical networking (MONET), is a method for communicating digital information using lasers over optical fiber. The method provides the next level of communication networks after Synchronous optical networking, SONET optical networks. MONET optical networks provide an even greater Bandwidth (computing), bandwidth capacity. This new method employs wave division multiplexing (WDM) technology for transporting large amounts of telephone and data traffic and allow for interoperability between equipment from different vendors. First developed by the secretive National Security Agency as author James Bamford points out in his book, "Body of Secrets: Anatomy of the Ultra-Secret National Security Agency". It was also discussed at the 1996 Military Communications Conference. ReferencesMultiwavelength Optical Networking Consortium(broken)''Multiwavelength Optical Networks - A layered Approach''by Thomas E. Stern and Krishna Bala''Body of Secrets: Anatomy of the Ultra-Secret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Routing And Wavelength Assignment
The routing and wavelength assignment (RWA) problem is an optical networking problem with the goal of maximizing the number of optical connections. Definition The general objective of the RWA problem is to maximize the number of established connections. Each connection request must be given a route and wavelength. The wavelength must be consistent for the entire path, unless the usage of wavelength converters is assumed. Two connections requests can share the same optical link, provided a different wavelength is used. The RWA problem can be formally defined in an integer linear program (ILP). The ILP formulation given here is taken from. Maximize: :C_0(\rho,q) = \sum_^ m_i subject to :m_i \geq 0, integer, i = 1, 2, ..., N_ :c_ \in , i = 1, 2, ..., P, j = 1, 2, ..., W :C^TB \leq l_ :m \leq 1_WC^TA :m_i \leq q_i\rho, i = 1, 2, ..., N_ N_ is the number of source-destination pairs, while m_i is the number of connections established for each source-destination pair. L is the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MPLS Local Protection
MPLS Fast Reroute (also called MPLS local restoration or MPLS local protection) is a local restoration network resiliency mechanism. It is actually a feature of resource reservation protocol (RSVP) traffic engineering (RSVP-TE). In MPLS local protection each label switched path (LSP) passing through a facility is protected by a backup path which originates at the node immediately upstream to that facility. This node which redirects the traffic onto the preset backup path is called the Point of Local Repair (PLR), and the node where a backup LSP merges with the primary LSP is called Merge Point (MP). This mechanism (local protection) provides faster recovery because the decision of recovery is strictly local. For comparison, when recovery mechanisms are employed at the IP layer, restoration may take several seconds which is unacceptable for real-time applications (such as VoIP). In contrast, MPLS local protection meets the requirements of real-time applications with recovery time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
